Selectors of the coordinate selector type



Dec. 17, 1968 s. o. VIGREN 'ETAL 3,417,353

SELECTORS OF THE COORDINATE SELECTOR TYPE Original Filed July 15, 1965 6 Sheets-Sheet 1 M F/G. 3. 63 1 4 F/G6.

INVENTORS STEN Q V/GRE'N ROLFAZANDER PER HdR/PYE. CLAESSO/V Dec. 17, 1968 s. D. VIGREN ETAL SELECTORS OF THE COORDINATE SELECTOR TYPE Original Filed July 15, 1965 6 Sheets-Sheet 2 I l I I I 11 A Ji .i

I ll! g ,l Q I l2 l1 2 II a =2: III

02 //0 I07 09 I04 I08 INVENTORS STE/VD. V/GRE/V ROLFA. ZA/VDER PERHARRYE. CLAESSON 7, 1968 s. D. VIGREN ETAL 3,417,353

SELECTORS OF THE COORDINATE SELECTOR TYPE Original Filed July 15, 1965 6 Sheets-Sheet 5 F/G//. 205 209 F/G /3.

F/G 205- F/G. /4.

v AIAIA=L 5:551. V v "1- 2/9 F/G /8. 2/7 225 F/G, /Z 18 2 INVENTORS 872W 0. V/GRE N ROLF A .ZANDER PER l-MRRY E. CLAESSON Dec. 17; 1968 s. D. VIGREN ETAL 3,

SELECTORS OF THE COORDINATE SELECTOR TYPE Original Filed July 15, 1965 6 Sheets-Sheet 4 F/G24 405 F/GZ/ a 406 j 4 0 40/b M W! 3 40m F/G 26. H6123 ll'h, fj at INVENTORS STEN D. V/GRE' N ROLF A. ZANDER PER HARRYE CLAESSO/V Dec. 17, 1968 s. D. VIGREN ETAL 3,417,353

SELECTORS OF THE COORDINATE SELECTOR TYPE Original Filed July 15, 1965 6 Sheets-Sheet 5 F/ci 30 k Q I L 302 3/0 F/0/9 K AAAA g ,m \I L! V 30/ 1 300 [307] 309 I 306 309 INVENTOR$ smv 0. V/GREN ROLFA. ZANDER PER HARRYE'. ClAfSSOV 1968 s. o. VIGREN ETAL 3,417,353

SELECTORS OF THE COORDINATE SELECTOR TYPE Original Filed July 15, 1965 6 Sheets$heet 6 F/G 25. K2 2 F/G 29. 5 ab 0 K000 00 L Q 0 0 INVENTORS S TEN 0 V/GRE/V ROI. FAZA/VDER PER l-MRR) E. CLAESSON United States Patent 3,417,353 SELECTORS OF THE COORDINATE SELECTOR TYPE Sten Daniel Vigren, Mosebacke Torg 16-18, Stockholm, Sweden, Rolf Albin Zander, Storhagsvagen 28, Alvsjo, Sweden, and Per Harry Elias Claesson, Osterhagens Gard, Drevviken, Sweden Continuation of application Ser. No. 472,170, July 15, 1965'. This application Nov. 15, 1967, Ser. No. 683,412 Claims priority, application Sweden, July 23, 1964, 8,991/ 64; Nov. 10, 1964, 13,519/64 12 Claims. (Cl. 335-412) ABSTRACT OF THE DISCLOSURE A shuntfield relay having an armature and two electromagnetic devices respectively forming first and second air gaps with the armature. When the electromagnetic devices are energized, one electromagnetic device produces a magnetic flux in a first direction across the first air gap and in a first direction across the second air gap, and the second electromagnetic device produces a magnetic flux across the second air gap in a direction opposite to the aforesaid first direction in addition to producing a magnetic flux across the first air gap in the aforesaid first direction, whereby energization of either of the electromagnetic devices alone results in a magnetic flux across the first air gap and the second air gap, while simultaneous energization of the electromagnetic devices results in addition of aiding flux in the first air gap and cancellation of opposing flux in the second air gap.

Related application This application is a continuation of the now abandoned application Ser. No. 472,170 filed on July 15, 1965 for Selectors of the Coordinate Selector Type.

A conventional telephone switchboard selector of the coordinate selector type is usually provided with mechanical cross-bars with spring pointers and bridges. Such selectors are rather complicated. The actuation of a contact spring group in a selector of that kind takes a rather long time, about 40 milliseconds, but due to the vibrations of the spring pointers, the time interval between two operations has to be extended to about 100 milliseconds. Because of the heavy magnetic circuits for the actuation of the cross bars and the bridge armatures, the selectors are heavy; each selector unit weighing between and 19 kilograms.

It has also been proposed to provide a coordinate selector with intersecting horizontal and vertical coils. Each of the intersections there is provided a relay of the socalled reed-relay type, each of the relay being provided with relay contacts. Apartfrom the fact that the reedrelays need a considerably bigger number of ampere-turns for their actuation than conventional relays, the reliability is poor.

When current of a magnitude of, for example, 100 ma. is supplied to one of the horizontal coils, the relays associated with said coil must not be actuated. But when current of the same order is also supplied to one of the vertical coils, that relay, which is located at the point of intersection between said coils, should be actuated. Thus, a reed-relay must not be actuated by a current of 100 ma.

but should be actuated with great certainty by a current of 200 ma. The theoretical limit between the current values for actuation and non-actuation is, therefore, ma. without tolerances. This gives very narrow manufacturing margins as the relay should not be actuated by a current of 125 ma. but be actuated by a current of ma.

The present invention relates to a coordinate selector with two intersecting groups of coils, such as intersecting horizontal and vertical coils, by which a broader margin between the values for actuation and nonactuation is obtained.

According to the invention a magnetic circuit of the shuntfield circuit type is provided at each point of intersection, each magnetic circuit having contact means actuated by such circuit. Each magnetic circuit comprises at least one magnetic core and a movable part, such as an armature, said movable part being adapted, upon energization, to actuate said contact means. One part of each magnetic circuit is enclosed in the horizontal coils passing the intersection point where said shuntfield circuit is located, while another part of said circuit is enclosed in the vertical coil passing said intersection point.

According to the principles on which the operation of a shuntfield circuit is based, there is a rather poor or practically no attracting force at all on the armature when current is supplied to only one of the intersecting coils, such as the horizontal coil, due to a short-circuiting of the generated magnetic flux. When the other coil (the vertical coil) is also energized, both the generated fluxes attract the armature together.

A selector of the coordinate selector type according to the present invention, gives the following advantages as compared with a conventional cross bar selector:

(1) A considerably lower price.

(2.) The current required for actuation may be considerably lower.

(3) The time for actuation may be reduced from about 100 milliseconds (for conventional selectors) to about 6 milliseconds.

(4) Complete safety is ensured with regard to the limits defining the conditions for actuation and non-actuation.

In the following, the invention will be described more in detail, reference being had to the accompanying drawings, in which:

FIG. 1 is a side elevation of a relay of the shuntfield magnetic circuit type,

FIG. 2 is a top elevation of the relay according to FIG. 1,

FIG. 3 is an end elevation of the relay according to FIG. 1,

FIG. 4 is a diagrammatical illustration of a part of a coordinate selector comprising a modified form of shuntfield magnetic circuit relays,

FIG. 5 is an illustration of the device according to FIG. 4 as viewed from the left in FIG. 4,

FIG. 6 is an illustration of the device shown in FIG. 5 as viewed from the bottom in FIG. 5,

FIG. 7 is a diagrammatical illustration showing the principle of a magnetic circuit for a coordinate selector according to a modified form of the present invention,

FIG. 8 is an illustration of a part of a coordinate selector involving magnetic circuits of the type illustrated in FIG. 7,

FIG. 9 illustrates the device of FIG. 8 as viewed from the left in said figure,

FIG. 10 is an illustration of the device according to FIG. 9 as shown from the bottom of said figure,

FIG. 11 is an illustration of a known relay involving the shuntfield magnetic principle,

FIG. 12 illustrates a modified form of the relay according to FIG. 11,

FIG. 13 illustrates a further modificaiion of said relay,

FIG. 14 illustrates still another modification of that relay,

FIG. 15 is an illustration of a part of a coordinate selector using relays of the type shown in FIG. 14, said relays being mechanically modified,

FIG. 16 is an illustration which shows more in detail one of the relays actually employed in the selector according to FIG. 15,

FIG. 17 is an illustration of the device according to FIG. 15 as viewed from the top of the last-named figure,

FIG. 18 is an illustration of the device shown in FIG. 17 as viewed from the right side of the last-named figure,

FIG. 19 is a diagrammatical illustration of a relay using the shuntfield magnetic principle according to a still further embodiment of the present invention, the relay being shown in the unactuated position,

FIG. 20 shows the relay according to FIG. 19 in the actuated position,

FIG. 21 illustrates a modified embodiment of the relay according to FIGS. 19 and 20, which is shorter and more compact, the relay being shown partly in section and in unactuated position,

FIG. 22 illustrates the relay shown in FIG. 21, in actuated position,

FIG. 23 is a top view of the relay according to FIGS. 21 and 22,

FIG. 24 is an end view of the relay according to FIG. 21 as seen from the right end,

FIG. 25 is a side view of the armature used in the relay according to FIG. 21,

FIG. 26 is a top view of said armature,

FIG. 27 is an illustration of a shuntfield relay of the so called reed-relay type, used in one embodiment of the present invention,

FIG. 28 is a simplified diagrammatical illustration of a telephone switchboard circuit according to the present invention,

FIG. 29 is a more detailed diagram of a part of a telephone switchboard using the principle illustrated in FIG. 28,

FIG. 30 is a bottom view of a shuntfield magnetic circuit relay according to a further embodiment of the present invention,

FIG. 31 is a side view of the relay according to FIG. 30, as shown in its unactuated condition, and

FIG. 32 is a side view of the relay as shown in its actuated condition.

The relay according to FIG. 1 comprises a relay bridge 1, an armature 2, cores 5 and 6 and a yoke 3, all said parts being of ferromagnetic material, such as iron.

The material in said parts should have a low coercive force, for example less than 1 oersted in the parts 1, 2, 3 and 6 and preferably a higher coercive force in the part 5, for example more than 2 oersted. The yoke 3 may be provided with a small air gap 4. The relay cores are provided with windings 7 and 8 as usual. 9 designates a contact spring group which may comprise just two contact springs as illustrated or may be composed of several contact springs.

When the winding 7 is fed with a magnetizing current, i

a magnetic flux F 1 will be generated which flows through the yoke 3, the core 6, the rear part of the bridge 1, and back to the core 5. Due to the fact that the air gap 4 is considerably smaller than the air gap between the armature and the end of the core 5, only a negligible part of the generated flux will pass through the armature and consequently the latter will remain unactuated. If the core 6 is magnetized in a similar way by a current flowing through the winding 8, a magnetic flux F2 will be generated and only a negligible part of said magnetic flux will pass through the armature which, also in this case, will remain unactuated. If, on the contrary, currents are supplied to the windings 7 and 8 at the same time, so that the fluxes F1 and F2 will be generated simultaneously, a very powerful flux will pass through the bridge 1 and the armature, and, therefore, said armature Will now be attracted. According to the present invention, the current through the windings 7 and 8 should be interrupted at the same time or the current through the Winding 8 should be interrupted before interruption of the current through the winding 7. In either case the remanent flux from the core 5 will continue to pass through the armature and through the bridge so that the armature remains attracted if the core Shas a relatively high coercive force. Because of the fact that the armature is now attracted, the air gap between the armature and the end of the core 5 is rather small, preferably smaller than the air gap 4, so that a considerable part of the flux F1 will pass through the armature. The coercive force of the core 5 should of course have such a value, that the armature with certainty will remain attracted.

The armature may be restored to its rest position by supplying a current solely to the winding 8, which current should pass the winding in the same direction as the magnetizing current. The flux F2 which is now generated will pass through the armature and the bridge and also through the core 5. The part of the flux which passes the core 5 will oppose the fiux F1 so that the core 5 is demagnetized. When, finally, the current through the winding 8 is interrupted, both fluxes F1 and F2 will cease to flow because the core 5 is now demagnetized. It should be observed, that even if the core 5 is magnetized in an opposite direction by the flux F2, such a condition will prevail for a short moment, that the flux through the armature is zero, and during this short period the armature will be restored to its rest position. The strength of the demagnetizing current pulse is, therefore, not critical.

Thus, the de-energization of the relay is accomplished by means of a current through the winding 8 which passes in the same direction as the magnetizing current. In many cases this is a great advantage especially in connection with electronic controlled circuits, where rectifying diodes or transistors are incorporated in the circuits. If the current should be reversed in circuits of that kind, a doubling of the number of circuit elements is generally required.

In the relay according to FIGS. l-3, the core 5 consists of steel with a rather high coercive force. As an alternative, this core may be made of iron with a low coercive force, and only a small part of the core may consist of a material with high coercive force, for example a material of that type which is used for permanent magnets. It is only necessary to design the core 5 in that way, that the magneto-motive force in oersteds is sufiicient to keep the armature attracted. If the coercive force is much higher than necessary, the energy which has to be supplied to the winding 8 for demagnetizing the core 5 in order to restore the armature to its rest position, has to be unnecessarily high.

It should further be observed, that the air gap 4 should have such a size, with respect to the variable air gap between the armature and the end of the core 5, that the flux through the armature is small when one of the windings is fed with current and the core is in its nonactuated position, but that a considerable part of the remanent flux will flow through the armature, when the latter is in its actuated position.

In FIGS. 4-6 a coordinate selector is illustrated which is composed of a plurality of relays of the shuntfield circuit type.

Two elongated, comb-like members are located in the direction of one of the coordinates, the x-coordinate, for each row of relays in said direction. For the uppermost row of relays the stems of said comb-like members are designated at and 13, respectively, for the middle row at 11 and 14, and for the lowermost row at 12 and 15. '(Only three rows are shown, but it will, of course, be understood that any number of rows may be provided, corresponding to the size of the selector.)

Each of the comb-like members has teeth, each tooth constituting one of the core parts in one of the Shuntfield relays.

Thus, the elongated stems 10 and 13 are provided with teeth 25, 26, 27 and 16, 17, 18, respectively. The rest of of the rows of relays are arranged in a similar way, which will be apparent from the drawing.

The comb-like parts 10, 11 and 12 of the three rows and the teeth projecting from said parts are of a ferromagnetic material with a rather high coercive force. The comb-like members 13, 14 and 15 of the three rows and the projecting teeth from said parts are of a material with a rather low coercive force.

Each of the teeth 25, 26, 27 projecting from the part 10 in the uppermost row of relays (as well as corresponding parts in the other rows) corresponds to the core 5 of the relays shown in FIGS 1 to 3. correspondingly, each of the teeth 16, 17, 18 projecting from the part 13 in the uppermost row of relays (as well as corresponding parts of the other rows) corresponds to the core 6 of the relay shown in FIGS. 13.

Each of the relay units is provided with an armature, said armature being designated at 34, 35, 36 for the uppermost row at 37, 38, 39 for the middle row, and at 40,

41, 42 for the lowermost row of relays.

Each armature actuates an actuating rib (such as the ribs 55-57 of the uppermost row of relays) which, in turn, in a manner known per se, is connected to contact springs in a contact group (multiple contacts). The core parts 1618 of said relay units are surrounded by a common winding 45, which corresponds to the winding 8 of FIG. 1. Thus, all the core parts 1648 in the x-coordinate direction in the uppermost row may be magnetized by said winding 45. It should be understood that each row of relay units substantially corresponds to one of the bridges with its associated bridge magnet in a cross bar selector of a conventional type.

A suitable number of such rows may be arranged in the direction of the y-coordinate though there are only three rows shown in the drawing.

Magnetization of the core parts 27, 3t) and 33, which are located in the direction of the y-coordinate, takes place by means of a common winding 52. It should be understood that the winding 52 corresponds to the cross bar magnet in a selector, of the conventional coordinate selector type. Similarly, the core parts 26, 29 and 32 are magnetized by means of a common winding 51 and the core parts 25, 28 and 31 are magnetized by means of a common winding 50. As will be apparent from FIG. 5, each of said windings comprises a coil for each relay unit actuated by such winding, so that each of said core parts of said relay units is surrounded by one such coil.

It will be understood from the previous specification, that none of the armatures is attracted if one or more of the windings in the direction of only one of the coordinates is supplied with current, so that the core parts surrounded by such windings are magnetized. If, for example, only the winding 45 is supplied with current, a flux F1 will flow in a circuit composed, for example, by the core parts 18 and 27 (see FIG. 4). If only the winding 52 is supplied with current, a number of core parts and among them the core part 27 will be magnetized, said magnetization causing a magnetic flux F2 which also flows in a circuit through the core parts 18 and 27.

If, on the contrary, the windings 45 and 52 are fed with current at the same time, the fluxes F1 and F2 will be forced to pass through the armature 36 and through the air gap between the movable end of said armature and the end of the core part 27. When the currents through said windings are interrupted (the interruption should preferably take place a little earlier in the winding 45 than in the winding 52), the remanent flux F2 will continue to pass through the armature, so that the armature will remain attracted. Similarly, the armature may be attracted by means of current pulses which are brought to flow simultaneously through the windings and 51, and the armature 39 will be attracted by means of current pulses flowing simultaneously through the windings 46 and 52. The pole surface of the armatures and/or the pole surface of the adjacent core part should preferably have a spherical form so that, to a certain degree, a flux constriction is obtained.

The armatures 3436 may be restored to their rest positions by means of a current pulse through the winding 45, so that a demagnetization of the core parts 2527 will be obtained or a reversing of the direction of the magnetization in said core part will be obtained. This demagnetization of the core parts 2527 corresponds to the deenergization of a bridge magnet in a cross bar selector of the conventional type.

It will be understood from the foregoing, that a coordinate selector composed of relays of the shuntfield magnet circuit type according to the present invention is very suitable for actuation by pulses, which means that it is very suitable for actuation by electronically controlled markers. The selector operates much more instantaneously than coordinate selector of hitherto known types primarily because there are no mechanically movable pointers, so that the two directions of the coordinates may be energized at the same time when one of the armatures should be actuated. In coordinate selectors of hitherto known types the bar magnet representing one of the coordinate directions has to be actuated first, and thereafter some time must pass, so that the pointer will come to a standstill, before the bridge in the other coordinate direction could be actuated. These operations take of course much longer time than the actuation of a selector according to the present invention, in which energization of the two coordinate directions may be made simultaneously.

It the selector is actuated by means of pulses it may sometimes be advantageous to provide for a retaining or holding current which keeps the attracted armatures in actuated position. When the armatures should be released in such a case, it is only necessary to interrupt the retaining current, which may be made simultaneously for a great number of coordinate selectors connected in series. If a selector according to the invention should be designed for that type of operation, all the magnet core parts should have a low coercive force and the windings in the direction of one of the coordinates, for example the x-coordinate direction, should be supplied with the retaining current. The retaining windings may preferably be placed on the magnet core parts, close to the armatures. In such a case the winding 45 would be placed around the core parts 2527 and the winding 52 around the core parts 18, 21 and 24. In that case, the flux from the retaining current need not pass the unavoidable, small air gaps between the core parts provided with windings.

It has already been mentioned that the contact spring groups of the multiple contact field may be arranged in a manner known per se. As an alternative, however, the armatures may be shaped as contact springs, in which case they should make contact against some resilient contact rib, so that the armatures are not prevented from reaching the pole end of the adjacent core part. Also the pivots of the armatures may be made in any suitable way, known per se.

Due to the fact that each contact spring group in the multiple contact field is actuated by its own armature, there is no risk of so called inherent blocking which occurs in conventional coordinate selectors, and which means that when a bridge magnet has been energized and one of its contact spring groups actuated, all the other contact spring groups belonging to said bridge are blocked.

Now a modified form of a coordinate Slector according to the present invention will be described with reference to FIGS. 7-10 of the drawing.

In FIG. 7 there are shown magnetic core parts 103, 104 and 105 which are connected to each other by means of cross pieces 101 and 102 of ferromagnetical material. These cross pieces are also connected to each other by means of a rib 106 which is also of ferromagnetic material. Each of the core parts 103, 104 and 105 has a winding 111, 112 and 113, respectively. Further, there is a winding 110 enclosing or surrounding all said three core parts. On one side of the winding 111 there is an armature 107 located. Similarly, there is an armature 108 belonging to the winding 112, and an armature 109 belonging to the winding 113.

If the winding 111 is supplied with magnetizing current of a predetermined direction, a flux F111 will be generated, said flux passing through the core part 103, the core parts 104, 105, and the rib 106. Only a small part of said flux will be flowing through the armature 107 because there is a rather big air gap between the core part 103 and said armature when the armature is in its unactuated position. The armature 1.07, therefore, is not attracted and neither is any one of the other armatures, because these armatures will be passed by a still smaller part of said flux.

If the winding 110 is supplied with a magnetizing current, there will be a flux F110 generated through the core part 103 and a flux of the same magnitude also through the other core parts. The rib 106 serves as a return path for said flux. Also in this case only a small part of the flux from the winding 110 will be passing through the armatures, because of the air gap between said armatures and the core parts, and, consequently, also in this case the armatures will not be attracted. If, on the other hand, the windings 110 and 111 are fed with currents simultaneously, said currents being of such mutual direction that the fluxes F110 and F111 oppose each other in the core 103, beneath the air gap between the left end of the armature 107 and the core part 103, a considerable part of the fluxes will be forced to pass through the armature 107, and in this case the latter will be attracted.

If all the parts of the magnetic circuit, such as the core parts, the cross pieces and the rib have a low coercive force, the armature will be released and restored to its rest position when the current is interrupted in both windings 110 and 111. If, on the contrary, the current is interrupted only in one of said windings, the armature will be retained in activated position, because the air gap between the armature 107 and the core parts 103 is now very small, so that a part of the flux generated by the winding, in which current still flows, passes through the armature. The core part 103 is preferably provided with a small air gap in that part of the core where the winding 110 is located, such as the air gap 114 close to the coil 110. This air gap should have such a size, that the part of the flux which is forced to pass through the armature when the coil 111 is supplied with a retaining current is sutlicient to keep the armature attracted.

If the core part 103 is made from a material with a relatively high coercive force or if there is a permanent magnet in said core part, a permanent flux will be obtained after the magnetizing currents have been supplied to the windings 110 and 111. Said permanent flux will retain the armature in actuated position after the currents through both windings 110 and 111 havebeen interrupted. In this case the currents should be interrupted simultaneously or the current through the winding 110 should be interrupted a little earlier than the current through the winding 111, so that the remanent flux F111 will be generated by the current through the last named winding. The armature 107 is, in this case, restored to its rest position by means of a current pulse through the winding 110,

which demagnetizes the core part 103 just in the same way as has been described in connection with the embodiment according to FIGS. 1-6.

It will be also evident that the armatures 108 and 109 may be attracted by supplying currents to the windings belonging to such armatures and to the winding 110. If the core parts in this case have a relatively high coercive force, so that the armatures will be retained in actuated position after the currents have been interrupted, all core parts may be dermagnetized by supplying a current pulse to the winding 110, said current pulse being of the same direction as the current used for the actuation of the armatures.

The device which has been described in principle in connection with FIG. 7, corresponds substantially to a bridge in a coordinate selector of a conventional construction. If a plurality of such devices (each comprising core parts with windings and ribs belonging to such core parts) are placed adjacent to each other or parallel to each other, said devices will form a coordinate selector. Such a selector will now be described with reference to FIGS. 8-10.

The parts 101113 shown in FIG. 7 are also shown in the lowermost bridge unit according to FIGS. 8 and 9 but the mutual arrangement of the armatures and the core parts is a little modified. There is also shown in FIGS. 8 and 9 a contact spring group 150. Further, there are shown in FIGS. 8 and 9 two additional bridge units comprising the following parts: The core parts for one of said bridge units are designated at 117, 118 and 119 and for the other at 133, 134 and 135. The magnetic cross pieces (corresponding to the cross piece 101 of FIG. 1) are designated at 115 and 116 for one of said parts and at 131 and 132 for the other of said parts. The ribs between the cross pieces are designated at and 136-, respectively. The armatures are designated at 122, 123 and 124 for one of said bridge parts and at 137, 138 and 139 for the other bridge part. The winding 111 is arranged to enclose the core parts 103, 117 and 133, Le. all the core parts in the same row in one of the coordinate directions, which corresponds to one of the bars in a cross bar selector of a conventional construction. Similarly, the winding 112 surrounds the core parts 104, 118 and 134 and the winding 113 surrounds the core parts 105, 119 and 135. The contact spring groups for said additional bridge units are designated 151 and 152.

In consideration of what has been stated above, in connection with FIG. 7, it will be evident that, for example, the armature 123 will be actuated if current is supplied to the windings 112 and 121 at the same time. Similarly, the armatures 123 and 133 will be actuated if'current is supplied to the windings 112, .121 and at the same time. It will also be evident, that the armatures 122, 123, 137 and 138 will be actuated if current is simultaneously supplied to the windings 111, 112, 121 and 140. As in the device according to FIG. 7, the core parts may be made from a material with low coercive force, the armatures being then retained in actuated position by means of a retaining current which is weaker than the actuating current and which flows through, for example, the windings 111, 112 and 113, said windings being partly surrounded by the armatures. Alternatively, the retaining current could be supplied to the windings 121 and 140. According to another alternative, the core parts may be made from a material with a rather high coercive force as the case was in FIG. 7, or a permanent magnet may be inserted in some of the core parts. In either case, the demagnetization of the core parts may be accomplished by supplying a demagnetizing current to the windings 110, 121 and 140.

Ribs corresponding to the ribs 106, 120 and 136 in FIG. 9 may, of course, be arranged also at the right side of the selector as seen in FIG. 9, outside the core parts 103, 117 and 133, whereby the return of the flux from the windings 110, 121 and 140 will be still further facilitated.

When an armature is actuated, such as the armature 137 in the row which comprises the armatures 137, 138

and 139, in one of the coordinate directions, the actuation of the armatures 138 and 139 may be prevented, it desired, by means of a mechanical arrangement. This mechanical arrangement comprises an elongated rod, with a cross section like a pawl, a catch or the like 145, which is tilted when one of the armatures is actuated. In FIG. 8 it is shown how the armature 137 is provided with an extension 146 which turns the rod 145 about a longitudinal axis 147 when the armature 137 is actuated. Each of the armatures is provided with such an extension, and the pawl-shaped rod 145 is extended over the ends of all such extensions of the armatures. When the rod 145 is tilted and the part 148 of the pawl is moved to the right, above the extensions 146 of the armatures which are not actuated, the movement of said extensions will be barred by said part 148 and the actuation of such armatures will be prevented.

In FIGS. 13 and 14 there is shown a shuntfield relay in which two air gaps for the armatures are provided, i.e. the normal actuating air gap and an auxiliary air gap, which is very small when the armature is in its rest position. The different core parts of the relay, the armatures, and the yoke, are so arranged that when only one of said core parts is magnetized, the flux in the auxiliary air gap securely keeps the armature retained in its rest position. But if both core parts are magnetized, the flux in said auxiliary air gap is eliminated due to the fact that a magnetic bridge circuit is established, so that the armature will be actuated by the pull force from the flux in the actuating or working air gap.

In FIG. 11 there is again diagrammatically illustrated a shuntfield relay of a known type. The core parts are designated at 201 and 202 and the windings of said core parts at 206 and 207, respectively. The core parts are connected to each other at one end of the relay by means of a yoke 204 and at the other end by means of a bridge 203.

The armature 205 is pivoted to the bridge 203 and will be attracted by the yoke 204. If current is supplied to the winding 206, so that a flux is generated in the core part 201, a portion of said flux will flow through the armature 205 and the bridge 203 and another portion through the core part 202. The portion of the flux through the armature will, of course, give rise to a pull force acting on the armature. If the air gaps between the two core parts and the yoke and between the yoke and the bridge are of equal dimensions, about half of the flux from the core part 201 will pass through the armature. If the core part 202 is magnetized by the same number of ampere turns as the core part 201, the flux portions through the armature will be doubled, if the magnetization takes place in the directions indicated by the arrows in FIG. 11. Because the flux through the armature only doubles, when actuation of the armature should take place, the security margins will be rather small. If, on the contrary, the core part 202 is magnetized in the reversed direction to the arrow shown in FIG. 11 and by the same number of ampere turns as the core part 201, the flux through the armature will be zero. A complete security with regard to actuation and non-actuation by known types of shuntfield relays will, therefore, be obtained only if the current in one of the windings is switched over to the opposite direction when the relay should be actuated. Therefore, it is evident that shuntfield relays of known types suffer from the disadvantage, that their dependability in certain cases is insufficient.

Also in FIG. 12 there is shown a shuntfield relay according to the same principle and functioning in the same way as the device according to FIG. 11. In the relay according to FIG. 12,'the core parts are serially arranged, and in that case the yoke 204 of FIG. 11 has been eliminated.

The core part 201 according to FIG. 11 as well as FIG. 12 may be made from a material with a rather high coercive force, and in that case the armature will be retained in actuated position due to the remanent flux, until the core part 201 is demagnetized. This demagnetization may take place either by supplying a current pulse to the winding 206 which counteracts the magnetization, or by supplying a current pulse to the winding 207 in the same direction as the magnetization current.

It the relay according to FIG. 12 is modified in a way which is illustrated in FIG. 13, two air gaps are obtained at one end of the armature, one of said air gaps being the working air gap 208 and the other an auxiliary air gap 209. This modification gives an increased dependability of the relay which will be evident from the following description.

It is assumed that current is supplied to the winding 206 according to FIG. 13 so that a flux is generated in the core part 201 in the direction of the arrow. A portion of said flux will be flowing through the air gap 208 and the armature 205 and will produce a certain attraction force to said armature. But a greater portion of said flux will pass through the core 202, the air gap 209 and the armature 205 and will retain the armature in the unactuated position. The air gap 209 is much smaller than the air gap 208 when the armature is in its unactuated position, and due to this fact, the flux through the air gap 20? will be stronger than the flux through the air' gap 208, and the attraction force on the armature in direction to the core part 202 in the air gap 209 will, therefore, also be stronger.

The case will be quite similar if the winding 207 is supplied with current instead of the winding 206 which will be evident from FIG. 13 without any further explanation. According to this embodiment there will be no risk at all for actuation of the relay armature when only one of the core parts 201 or 202 is magnetized.

If, on the contrary, the windings 206 and 207 are fed with a current simultaneously, so that two fluxes in the directions of the arrows in FIG 13 are generated, it will be evident that when the drop in the magneto-motive force between the parts of the cores which are located adjacent to the air gap 208 and that end of the core part 202, which is located adjacent to the air gap 209, is equal to the drop in the magneto-motive force between said parts of the cores 201 and 202 which are adjacent to the air gap 208 and that end of the armature 205 which is adjacent to the air gap 209, the flux through the air gap 209 will be zero, so that the attraction force from the flux in the air gap 208 will actuate the armature. Thus, the different parts of the relay are incorporated in a magnetic bridge circuit, which has its point of equilibrium in the air gap 209. When the relay is to be actuated, the winding 207 is preferably supplied with a current a little later than the winding 206, and with current of such a direction, that the direction of the flux through the air gap 209 will reverse direction. In that case, the armature will start its movement when the flux through the air gap 209 approaches zero, and the fiux will obtain very small values after the reversal has taken place, because in the meanwhile the air gap 209 has been increased. Because of this fact, the values of the magnetization current through the windings 206 and 207 may vary within very wide limits without jeopardizing the proper operation of the relay. Thus, it is evident that a dependable operation of the relay will be obtained because of the auxiliary air gap 209.

If the core part 201 according to FIG. 13 is made from a material with a high coercive force, a reman:nt flux will be obtained in the same way as in the embodiment according to FIGS. 11 and 12, which remanent flux will keep the armature in its actuated position after the magnetizing currents have been interrupted, first in the winding 207 and thereafter in the winding 206. Thus, the relay may be demagnetized by supplying to the winding 206 a current pulse in the opposite direction as compared to the magnetization current, or by supplying to the winding 207 a current pulse in the same direction as the 11 magnetization current. In the latter case, a flux from the winding 207 will pass over to that end of the core part 201 which is remote from the air gap 208, partly by leakage and partly by passin the air gap 209, which 3 exists between the armature 205 and the core part 202.

Practical tests have shown that a sufiicient demagnetization of the core. part 201 will be obtained when the core part 202 is magnetized by about the same number of ampere turns, as when the relay was magnetized.

The same shape of the armature according to FIG. 13 may be modified in a manner illustrated in FIG. 14. In this modification, the auxiliary air gap 209 is located at the end of the core part 202, which is remote from the air gap 208. The operation of this relay will be the same as the operation of the relay shown in FIG. 13, but the demagnetization by means of the curent pulse through the winding 207 will be more efiicicnt than in the relay shown in FIG. 13. The core parts 201 and 202 according to FIG. 14 are connected to each other by means of point welding or riveting.

A part of a coordinate selector, composed of relays of the type shown in FIG. 14, is illustrated in FIGS. 15-18. The relays in this selector comprise core parts 211, 212 and 213'(as well as 214, 215 and 216 which are not shown in the figure). Said core parts are preferably made from a magnetic material with a relatively high coercive force, for example 40 oersteds. These parts correspond to the core part 201 according to FIG. 14. Said core parts are connected to other core parts 217 to 222, respectively, which correspond to the core part 202 according to FIG. 14. The armatures of the coordinate selector are designated at 223-228. A coil 230 encloses the core parts 211, 212 and 213 and a coil 231 encloses the corresponding parts 214, 215 and 216 in the same coordinate direction. The coils 230 and 231 are located between arms belonging to the armatures and, therefore, they do not enclose or surround said armatures. A coil 232 encloses the core part 217 and 220 and, correspondingly, a coil 233 encloses the core parts 218 and 221. Finally, a coil 234 encloses the core parts 219 and 222. The core parts 211, 212 and 213 are, by means of screws 241, 242 and 243, fastened to a. rib 240 of magnetic material. The cross section of said rib 240 of magnetic material is profiled as illustrated in FIG. 18.

One of the armatures viz., the armature 223, will now be described more in detail, with reference to FIGS. 16 and 18. The armature comprises a part 239 which passes the end of the core part 217, so that the auxiliary air gap 209 will be obtained between said core part 217 and the armature. Further, the armature comprises two arms 244 and 245, which are parallel to the core part 217, and two arms 246 and 247 which are parallel to the core part 211. Said parts of the armature are all integral with each other and punched out of sheet material, and they are connected to each other by a part 248, which is also integral with the other parts. The arms 246 and 247 are inserted in recesses 249 and 250 in the rib 240. The armature is prevented from sliding out of said recesses in the rib 240 by the ends of the arms 246 and 247 of the armature, which abut against an adjacent flange of the coil 232. Where the part 248 of the armature passes the core part 217 the working air gap 208 is located.

In each point of intersection of the different coils of the coordinate selector, a contact spring group is located. According to the drawing, each of said contact spring groups comprises two contacts. Each contact spring group comprises two movable contact springs and two fixed contact ribs, said contact ribs being commonfor all contact spring groups located in one row in the same coordinate direction. A contact spring group of said kind will now be described more in detail, said contact spring group being located at the point of intersection between the coils 230 and 232, i.e. at the same intersection point as the armature 223. The contact ribs 250 and 251 are fastened to a plate 254 of an insulating material, said plate having an aperture which is forced over the end of the core part 207 against the winding 232. The contact ribs are located at different sides of said insulation plate and are fixed to the plate by means of lugs, which are bent around the edge of said plate, as will be evident from FIG. 15. The contact springs which belong to one row, perpendicular to the coordinate direction of the contact ribs (such as the springs 256 and 258), are preferably connected to each other at the fastening ends of such springs. Said springs may project from a metal rib which is common to one row and which is passing from one spring to the next at the rear side of the selector. The springs are bent and folded around a plate 260 of insulating material in a way which will be evident from FIG. 18. Apertures are provided in the rib 240. The contact springs which are fastened to the insulating plate 260 are freely passing through said apertures so that the insulating plate 260 abuts against the rib 240. After the pushing in of the contact springs, the free ends of said contact springs are twisted through and in this way the springs are fixed to the insulating plate 260. By this construction an electrical connection between the contact springs of one row will be obtained in a very simple and convenient way.

It is evident from FIG. 17, that the movable contact springs are fastened at one side of the coils 230, 231 which are. provided for one of the coordinate directions, and that they are actuated at the other side of such coils. Most of the movable contact springs (such as the contacts 258, 259, FIG. 15) are passing right through one of said coils (such as the coil 230, FIGS. 15 and 17). This is a very convenient and space-saving solution of a difiicult constructional problem.

The movement of the armature 223 is transmitted to the contact springs by means of a rib 261, which is fastened to the armature. The rib 261 is forced into recesses which are provided in the arms 246 and 247 of the armature, in a way which will be apparent from FIGS. 16 and 17.

A desired number of ribs 260 may be placed adjacent to each other so that the wanted size of the selector is obtained. In the drawing, only two such ribs are shown. Similarly, a desired number of relay units may be placed on each rib. In the drawing, only three such units on each rib are shown. The size of the winding coils must, of course, be increased in the same proportion as the number of ribs and the number of relay units is increased.

The operation of the selector according to FIGS. 15 to 18 is the following: When only one coil is supplied with magnetizing current (regardless of the coordinate direction of such coil) none of the armatures will be actuated due to the fluxes flowing through'the auxiliary air gaps. (Compare FIG. 14.) If, on the contrary, one coil in each coordinate direction is fed with current simultaneously, the armature which is located in the point of intersection between such coils will be actuated the same way as already described in connection with FIG. 14, when the windings 206 and 207 were supplied with magnetizing currents at the same time. Therefore, if the coils 230 and 232 are fed with current, the armature 223 will be attracted. If a plurality of coils are fed with current simultaneously in each coordinate direction, all the armatures which are located at the points of intersection between such coils will be attracted.

Demagnetization of a relay unit may take place in two different ways, just as has been described in connection with FIG. 14. Either the coils, which enclose the core parts with high coercive force, may be supplied with currents in directions contrary to the directions of the magnetization currents, or the coils which enclose the core parts with low coercive force may be supplied with current pulses in the same direction as the magnetizing currents through such coils.

The different armatures may, of course, be actuated in any desired order, but as the coils which enclose the core parts with low coercive force, have a demagnetizing effect on the core parts which have a high coercive force and belong thereto, one must make sure, that the armatu-res which are already actuated are not released. This may be accomplished by supplying a current at the same time to the coils which enclose the core parts with a high coercive force.

Alternatively, all the core parts may have a low coercive force, but in that case a retaining current must be supplied to the coils which enclose the core parts which, according to the foregoing, should have had a high coercive force. In that case, the relays are demagnetized by interruption of the retaining current.

In FIGS. 19 and 20, a shuntfield relay of a modified construction is shown, said shuntfield relay being suitable for that type of coordinate selector which is illustrated in FIGS. 1518.

By means of the shuntfield relay according to FIGS. 19 and 20 a still better retaining force on the armature will be obtained and the required strength of the demagnetization current may be lower than in the relay according to FIGS. 1214.

In the shuntfield relay according to FIGS. 19 and 20 there is a third air gap designated at 310, said air gap being provided at the free end of the armature. The air gap 310 is very small when the armature is in actuated position and it is so located that the flux for retaining the armature in actuated position partly passes through said air gap and partly through the first or working air gap which is designated at 308.

FIG. 19 illustrates the relay with the armature 305 in its non-actuated or rest position, while FIG. 20 shows the relay when the armature is actuated. The relay comprises a core, which, according to the embodiment illustrated, is divided in two parts 301 and 302, said parts being united to each other. Each of said core parts is provided with a winding 306 and 307, respectively. In this case, the two core parts may be made from material with different coercive force; the core part 301 preferably having a rather high coercive force and the core part 302 a rather low coercive force. The armature 305 extends along said core parts 301 and 302. According to the illustrated embodiment, the relay is provided with a first air gap, the working air gap 308, and a second or auxiliary air gap 309, said air gaps corresponding to the air gaps 208 and 209, respectively, of the relay shown in FIGS. 13 and 14, but in this case there is also a third air gap 310.

It has been possible to arrange these three air gaps by giving that end of the armature, which is remote from the pivoting point, the shape of a U, the shanks of said U being located at different sides of the core part 302. it will be evident from FIGS. 19 and 20, that the air gap 310 is smaller when the armature is actuated than when the armature is in its rest position.

It is also possible to make the core parts 301 and 302 of a material with the same coercive force, and in that case it is preferable to make said core parts integral with each other.

Regardless of whether the winding 306 or the winding 307 or both are used as retaining windings, the relay should preferably be designed in such a way, that at least the third air gap 310 is very small, i.e. that the armature is in direct contact with the core part 302 when the armature is actuated, but this does not exclude the possibi'ity that also the first air gap 308 may be small. Alternatively, it may be possible to adjust the first air gap 308 and the third air gap 310 with regard to each other just as desired (they may be different, they may be equal) in order to obtain any desired or predetermined magnetization conditions of the relay.

When the relay is being actuated, its operation is very similar to the operation of the relay shown in FIG. 14. When the armature is in its actuated position, shown in FIG. 20, and the third air gap 310 is small (e.g. smaller than air gap 308), a rather great part of the flux from the core part 301 (which preferably is remanent) will pass through the third air gap 310, and the retaining force of the armature 305 is, therefore, strong. Said force will, of course, cause a greater momentum to act on the armature 305 than an equal force acting in the first air gap 308, because the air gap 310 is located farther from the pivoting point than the air gap 308. Also when the relay is being released, i.e. when the core part 301 is being demagnetized, the third air gap 310 is of advantage, because, due to said air gap, the required demagnetization ampere turns may be decreased. The flux from the winding 307 will have a return path through the upper shank of the U-shaped part of the armature 305, i.e. through that shank of the U-shaped part which is in contact with the core part 302 (see FIG. 20). The third air gap is very small and has a very small magnetic reluctance when the release of the armature commences.

Practical tests have shown that if the third air gap 310 has a size of the order of, for example, 0.05 mm. or less, when the armature is in its actuated position, and the first air gap 308 should preferably be of the order of 0.2 mm. for obtaining a suitable strength of the demagnetization flux in the core part 1. If the first gap 308 is too small, too much flux from the core part 302 will pass through the first air gap 308 during the demagnetization process so that the demagnetization will be more uncertain. Said dimensions of the air gaps are based on a magnetization force of the order of oersteds.

Practical tests have also shown that the armature is also released to its rest position immediately after current has been supplied to the winding 307, when a rather weak demagnetization force (30-60 oersteds.) is used. If a greater number of ampere turns is used, the armature will be restored to its rest position when the current through the winding 307 ceases, because said current through the winding 307 gives rise to such a powerful flux through the third air gap 310, that the armature will remain in its actuated position until said current is interrupted.

It should be observed in this connection, that it is possible to make a relay with a third air gap also by other means than by means of the U-shaped armature which is illustrated in the drawing.

In FIGS. 21 to 26 a relay is illustrated, which has three air gaps, just as the relay according to FIGS. 19 and 20, but which is modified in some respects in order to get a shorter and more compact construction.

FIGS. 21 and 22 are cross sectional views of the relay, FIG. 21 showing the relay in unactuated position and FIG. 22 in actuated position. FIG. 23 is a top view and FIG. 24 is a rear view.

The relay comprises two core parts 401 and 402 (corresponding to the core parts 301 and 302 according to FIGS. 19 and 20). The core part 401 is composed of two parts 401a and 4011). At least one of said parts is preferably made from a material with a rather high coercive force, say about 30 oersteds. The parts 401a and 401b are joined to each other by welding or the like.

The core part 402 is made of a material with a low coercive force. It may be fastened to the core part 401 by welding.

The relay also comprises an armature 405 of a special shape. Said armature is shown more in detail in FIGS. 25 and 26.

The armature 405 comprises an angle-shaped portion 405a. In one of the parts of said angle-shaped portion, an aperture 405b is provided. As will be apparent from FIGS. 21 and 22, the free end of the core part 402 extends through said aperture 405b. To the other part of said angle-shaped portion two arms 405a and 405d are connected. All said parts of the armature are integral with each other and constitute different parts of a common blank, which is punched out from a steel sheet material with a low coercive force.

I The arms 405a and 405d abut with their ends against projecting side portions of the part 401).: of the core part 401 and with their bottom edges against lugs 4010 which are projecting from said side portions as shown in FIGS. 21 and 22.

The corner between the rear ends and the bottom edges of the arms 405a and 405d are chamfered as shown in the figures, in order to facilitate the tilting of the armature. When the relay is actuated, the armature is tilted from the position shown in FIG. 21 to the position shown in FIG. 22.

The relay comprises two windings, viz. one winding 406 on the core part 401a, and one winding 407 on the core part 402, said windings corresponding to the windings 306 and 307, respectively, in the embodiment according to FIGS. 19 and 20.

There are three air gaps in the relay, viz. a working air gap 408 between the front end of the core part 401a and the flat top part of the angle-shaped portion 405a of the armature 405, a second air gap 409 between the free end of the core part 402 and one of the surfaces defining the aperture 405b, and, finally, a third air gap 410 between the free end of the core part 402 and the opposite surface defining the aperture 405b. Said three air gaps 408, 409 and 410 correspond to the air gaps 308, 309 and 310, respectively, shown in FIGS. 19 and 20.

The operation of the relay according to FIGS. 21 to 26 corresponds exactly to the operation of the relay shown in FIGS. 19 and 20, and needs no further description.

The relay according to FIGS. 21 to 26 is very suitable for use in coordinate selectors of the type described in connection with FIGS. 16 to 18. The selectors thus obtained will be very compact and, at the same time, very inexpensive due to the simple construction of the relays.

In the relay types described in the foregoing, only the fixed core parts of the magnetic circuits are provided with magnetizing windings. It will be evident to anyone skilled in the art, that in most of the relays shown, it is possible to arrange one or both of the windings on suitable part of the armature instead of on the core parts.

In FIG. 27 there is illustrated a shuntfield relay of the reed relay type, in which the contacts are provided directly on movable parts 'of ferromagnetic material, and in which said parts are hermetically enclosed in a glass envelope. The actuating windings are located outside said envelope.

The relay according to FIG. 27 comprises a core part 502, which is composed of a rod 502a, a yoke 502b and a rod 5020. The rods extend through the yoke through apertures in said yoke. The rods are in good magnetic contact with the yoke but at least one of them is electrically insulated from the yoke. The rods 502a and 5020 as well as the yoke 502b are made from a material with low coercive force, say less than one oersted. The core part 502 corresponds to the core part 202 in the relay according to FIG. 13. Further, the relay comprises a core part 501, said core part being composed of a rod 501a, a yoke 50111 and a rod 501c. One end of the rod 501c is welded to the rod 5020 of the core part 502 by a joint 500.

The core parts 501a and 5010 extend through apertures in yoke 501b. They are in good magnetic contact with the yoke but at least one of them is electrically insulated from the yoke.

At least the rod 501s of the core part 501 should have a rather high coercive force, say about 30 oersteds, if the relay should be designed to keep the armature attracted after actuation without any retaining current through one of its windings.

To the free end of the rod 501a an armature 505 is fastened by means of a short, flat spring 510. Said spring 510 is fixed to the rod 501a by spot welding 511 and to the armature by spot welding 512. The armature 505 overlaps the end of the rod 501a as illustrated in order to make good magnetic contact with the rod, independent of the material in the spring 510. But preferably the spring 510 should be made from sheet steel.

The free end of the armature 505 is provided with a wart 513, 514 on each side of-the armature. The warts 513, 514 are of ferromagnetic material but on their surfaces there are deposited layers of some good contact metal, such as palladium.

In the position shown in the drawing, the wart 513 is pressed against the rod 502a with a suitable contact pressure. The surface on said rod, against which the wart is pressed, is also provided with a layer of contact metal.

Between the wart 514 of the armature 505 and the rod 5010 there is an air gap 508 which'corresponds to the air gap 208 of the relay according to FIG. 13. Said air gap 508 is the working air gap of the relay. The surface of the rod 5010 is provided with a layer of contact metal adjacent to the air gap 508, so that the armature, when it is actuated, will make good electrical contact with said rod 501a; There is also a magnetic air gap 509 between the wart 513 and the rod 502a. Said air gap is very small when the armature 505 is in rest position (as shown). Said air gap is then equal to the thickness of the contact metal layers of the wart 513 and the rod 502a. The air gap 509 corresponds to the auxiliary air gap 209 of the relay shown in FIG. 13.

The relay according to FIG. 27 also comprises two windings, viz one winding 506 surrounding the rod 5010 and one Winding. 507 surrounding the rod 5021:. The winding 506 corresponds to the winding 206 and the winding 507 to the winding 207 of the relay shown in FIG 13.

The contact parts of the relay are hermetically enclosed in a glassenvelope 515 as shown.

In the relay according to FIG. 27 there is no separate c-ontactspring group. The armature 505 with its contact warts 513 and 514 serves as the movable contact spring of the relay. The rods 5010 and 502a constitute the fixed contacts.

The operation of the relay according to FIG. 27 is quite similar to theoperation of the relay according to FIG. 13 and needs no further description. I

The relays which have an auxiliary air gap, such as, for example, the air gap 209 of the relay according to FIG. 13, are actuated partly. by the attraction force in the working air gap 208 and partly by the cessation of the retaining force in the auxiliary air gap209.

The principle involved in the action of the auxiliary air gap 209 can be said to be that a magnetic flux flowing round in a closed magnetic loop, in which said air gap 209 is included, is nullified by a counteracting magnetomotive force. It would be possible, at least theoretically, to substitute a spring or a permanent magnet'attraction force for the attraction force acting in the working air gap 208, and to operate the relay only by the magnetic force of the air gap 209.

But a much safer operation is, of course,-'obtained when the combination of the working air gap 208 and the auxiliary air gap 209 is used. 1

The safety of the operation is increased still more when the third air gap 310 according to FIGS. 19 and 20 is added to said combination.

By using one or more shuntfield coordinate selectors (or other type of coordinate selectors with crossing coils) as primary selectors or calling selectors in a telephone switchboard, it is possible to employ one of the relay units of the selector as a break relay for each subscriber connected to such selector.

It will be apparent from FIGS. 4 and 5 that the selector shown in said figures needs only a slight modification of the contact ribs with which the contact springs actuated by the actuating ribs 55-57 cooperate, in order to obtain break contacts instead of make contacts. Said contact ribs have only to be bent so that the contact surfaces thereof are located beneath the contact springs instead of above 17 them as illustrated, and that the contact surfaces of the contact springs are located on the undersides instead of the oversides thereof.

A similar modification may also be made in the selector according to FIGS. to 18. In this case it would be necessary to modify the cross section of the contact ribs 250, 251 in order to obtain the desired break functions.

The function of the break relay, which is used for each subscriber in a telephone switchboard of a conventional type, is to keep the subscriber connected to an identification device when the subscriber has initiated a call. As soon as the subscriber initiates a call by lifting the handset of this telephone instrument, the identification device in the switchboard is put into operation, and as soon as the subscriber has been identified, the break relay interrupts the connection between the subscriber and said identification device.

It is necessary that the contacts, by means of which said interruption is made, are individual for each subscriber and can be actuated independently of corresponding contacts for other subscribers. Therefore, if the primary selector in the telephone switchboard is a coordinate selector of the conventional cross-bar type, it would be possible to arrange said individual break contacts in connection with each contact spring group actuated directly by a bridge magnet in such selectors. It is possible to use such an arrangement only in such types of switchboard circuits where a bridge in the primary or calling selector is allotted to each subscriber. But such an arrangement is generally a rather expensive circuit solution and, therefore, in most of the known constructions a separate break relay for each subscriber is provided in the switchboard.

By using a selector with crossing coils and especially by using a shuntfield selector of a type described in the foregoing, each relay unit may be actuated quite independently of other relay units and, therefore, it is possible to arrange the contacts for said break function among the multiple contacts of the selector. This is an important simplification as compared with conventional switchboards, which leads to more compact, less expensive and more reliable constructions.

In FIG. 28 there is illustrated a very simplified circuit showing in principle the break contacts for the telephone instrument of a subscriber ab, said instrument being connected over a line L to the contact ribs K of a coordinate selector of the shuntfield type. The ordinary line relay belonging to the subscriber is simply shown as a resistor R. There is also a capacitor C connected in parallel to said resistor. The purpose of this capacitor is to provide a short circuit path for noise voltage appearing on the subscribers line L.

The line relay R and the capacitor C are connected between the negative poll of a current supply source and a break contact BR1 belonging to a pair of such contacts, the other contact of said pair being designated at BR2. The pair of contacts BR1 and BR2 belong to the multiple contacts of the selector. The contacts BR1 and BR2 are cooperating with the ordinary contact ribs K1 and K2, respectively, of the selector.

When the subscriber ab initiates a call by lifting his telephone receiver from its cradle, the following circuit will be closed: Positive, multiple contact BR2, contact rib K2, one part of the line L, the telephone instrument ab, the other part of the line L, contact rib K1, multiple contact BR1, the line relay R, negative. Due to the voltage drop in the resistance of the line relay R (or a separate resistor connected in series therewith), the potential of the multiple contact BR1 will be changed in the positive direction. An identification conductor S is connected between said multiple contact BR1 and the identification devices incorporated in the telephone switchboard. Because of the said change in potential the subscriber ab will be identified, and, when this is done, the contacts BR1 and BR2 will break so that the described circuit is interrupted.

The selector is also provided with a number of make contacts MK cooperating with the contact ribs K1 and K2, said make contacts being arranged to connect the calling subscriber, after identification, to the usual devices which are necessary to complete the connection.

In FIG. 29, there is illustrated how sixty-four subscribers may be connected to four selectors V1 to V4 and how eight outgoing links U2 and U3 are connected to said selectors. Each of the selectors V1 to V4 comprises eight contact ribs, two of which are shown in the drawing. Each contact rib is divided into two parts. To each such part a subscribers line is connected. (In the drawing, the subscribers lines and contact ribs are shown as single lines and single ribs. In practice, there will be two conductors for each subscriber and the ribs will be arranged in pairs as usual.)

Thus, the selector V1 comprises the contact rib parts K00, to K15, of which K00, K01 and K14, K15 are shown, to which the subscribers lines 00, 01 and 14, 15, respectively, are connected. Each contact rib cooperates with three make contacts K00a, K00b, K000 and K01a, K01b, K010, respectively, for the contact ribs K00 and K01. Each of said multiple contacts is connected to the corresponding multiple contacts of at lea:t a group of the other contact ribs. The multiple contacts of each such group, which are connected to each other, are, in turn, connected to an outgoing link incorporated in one of the groups of links U2 or U3. Thus, the multiple contacts K00a for the rib K00 are connected to the corresponding multiple contacts for all the contact ribs belonging to subscribers with even numbers, up to the contact rib K26. This group of multiple contacts is, in turn, connected to the outgoing link U2a of the group U2. Similarly, the multiple contact K00b is also connected to the corresponding contacts for other contact ribs belonging to subscribers with even numbers up to number 62, the said group being connected to the outgoing link U2b of the group of links U2.

The multiple contact K000 is connected to the corresponding contacts of other contact ribs for subscribers with even numbers up to number 30 only, said group being connected to the outgoing link U30 of the group U3.

The multiple contact K320 belonging to the contact rib K32 is connected to the corresponding contacts of the contact ribs for the subscribers with even numbers from 32 to 62, said group being connected to the outgoing link U32c of the group of link U3.

The multiple contact K010 of the contact rib part K01 is connected to all the corresponding contacts for the contact ribs belonging to subscribers with odd numbers up to number 63, said group being connected to the outgoing link U2a of the group of links U2. Similarly, the multiple contact K0117 is also connected to all corresponding contacts for all the contact ribs belonging to subscribers with odd numbers up to number 63, said group of multiple contacts being connected to the outgoing link U2b of the group of links U2.

The contact K010 of the contact rib K01 is connected to the corresponding contacts of other contact ribs for other subscribers with odd numbers up to number 31 only, said group being connected to the outgoing link U30 of the group of links U3. The multiple contact K330 of the contact rib K33 is connected to the corresponding contacts of other contact ribs for subscribers with odd numbers from number 33 to number 63, said group being connected to the outgoing link U330 of the group of links U3.

Each of the contact rib parts of the selectors V1, V2, V3, V4 cooperates also with a break contact, said break contact being designated at Br00 and Br01 for the contact ribs K00 and K01, respectively. Each break contact is connected to a line relay device, said line relay devices being shown only for the break contacts Br00 and Br01 and designated at LR00, and LR01, respectively.

To each of the break contacts there is also connected a conductor (not shown) corresponding to the conductor S of FIG. 28, leading to the identification device (not shown) of the switchboard.

In order to increase the capacity of the switchboard, there are two additional selectors V5 and V6, to the multiple contact of which the subscribers lines to 63 are connected. Said selectors have, in all, eight contact ribs ak1 to ak8, and to these contact ribs there are eight additional outgoing links U11 to U18 connected. Said contact links constitute together a third group of outgoing links designated at U1.

The selectors V and V6 have only make contacts in the contact multiple (no break contacts are needed here as the break functions are taken care of in the break contacts .of the selectors V1 to V4).

By the illustrated principle of connecting the subscribers lines and the outgoing links, a very favourable distribution of the traffic through the switchboard is obtained. It is apparent from the drawing, that each of the links belonging to the group U1 is accessible to eight subscribers only. Each of the links belonging to the group U3 is accessible to sixteen of the subscribers and each of the links belonging to the group U2 is accessible to thirty-two of the subscribers. Therefore, the switchboard should be designed in such a way (in a manner known per se), that in the first hand a link belonging to the group U1 is seized by a calling subscriber and, in the second hand (when all links in the group U1 are busy), a link belonging to the group U3. When all links belonging to the groups U1 and U3 are busy, a link belonging to the group U2 should be selected.

It is also possible to let one of the contact groups cooperating with each contact rib part perform that function for the subscriber connected to said contact rib part, which in an ordinary switchboard is performed by a separate line relay for such subscriber. This contact group may comprise make contacts and break contacts depending on the construction of the rest of the switchboard circuits.

The general principle of a switchboard described in connection with FIGS. 28 and 29 may be used in switchboards of any size.

In FIGS. 30 to 32 there is illustrated a relay of the shuntfield type according to a still further embodiment of the present invention, FIG. 30 being a bottom view and FIGS. 31 and 32 being side views showing the relay in unactuated and actuated positions, respectively.

The relay comprises an elongated core, consisting of two integral core parts 601 and 602, an armature 605 is located in parallel wit-h the core 601, 602 and has a down-bent portion 611 at one end, which is articulated to the outer end of the core part 601. The other end of the armature 605 has also a down-bent portion 612, between which and the outermost end of the core part 602 there is a working air gap 608.

The armature 605 is provided with two lugs 613, 614- at the central part thereof. Said lugs are bent downwards towards the core 601, 602 and beyond said core, and inwards, towards each other, so that they embrace the core which will be apparent from FIG. 30.

Between the free ends of said lugs 613, 614 and the bottom side of the core 601, 602 there is an auxiliary air gap 609. The auxiliary air gap is small when the relay is in its non-actuated condition (FIG. 31) but its length increases as the relay is being actuate-d (FIG. 32).

There is one winding 606 surrounding the core part 601 and another winding 607 surrounding the core part 602.

The parts of the relay, which are designated at 601, 602, 605, 606, 607, 608 and 609 correspond to the parts of the relay illustrated in FIG. 13 which are designated at 201, 202, 205, 206, 207, 208 and 209, respectively.

In operation, when a current is supplied to, for example, only the winding 606, a flux will be produced through the core part 601 (in the direction of the arrow 614a), through the articulation joint 611, through the right hand part of the armature 605, through the projecting lugs 613, 614 (in the direction of the arrow 615, FIG. 31), through the auxiliary air gap 609 (which is very small), and back to the core part 601. The armature will be locked in its rest position by the force produced in the air gap 609 and no actuation of the armature will take place. If a magnetizing current is fed only to the winding 607 a flux will be produced in the core part 602 (in the direction of the arrow 616, FIG. 31), through the auxiliary air gap 609, through the lugs 613, 614 (in the direction of the arrows 617, FIG. 31), through the left hand part of the armature 605, through the working air gap 608 (which is now rather big) and back to the core part 602. This flux will exert a stronger attraction force in the small auxiliary air gap 609 than in the bigger working air gap 608. Also in this case no actuation of the relay will take place.

If magnetizing currents are supplied to both windings 606 and 607 at the same time, both fluxes will be generated simultaneously. It is evident from FIG. 31 that said fluxes oppose each other in the path provided by the lugs 613, 614 and in the auxiliary air gap 609. If the fluxes are of equal strength the attraction force in the air gap 609 will be zero. Now the armature will be attracted to the core by the flux through the air gap 608. During the movement of the armature, the air gap 609 will increase and the air gap 608 will decrease. This means, that practically no magnetic flux will pass through the lugs 613, 614. The fluxes generated by the windings 606 and 607 will be connected in series and cooperate to attract the armature.

When actuated, the armature may be retained in this position by a retaining current through one of the windings 606 or 607. This retaining current should be much weaker than the magnetization current, so that it will not be sufiicient to attract the armature of the non-actuated relays (in the same row as the coil supplied with such current), when one of these relays is supplied with magnetizing current in the other coil. Preferably, the ratio of the magnetizing current and the retaining current should be of the order of six to one. Preferably, the retaining current should be supplied to the winding 607, because this winding produces a rather strong magnetic flux in the actuated relay (the air gap 608 being small) but a rather weak flux in the non-actuated relays (the air gap 608 being big).

We claim:

1. A shuntfield relay, comprising an armature, first magnetic means forming a first air gap with said armature, second magnetic circuit means forming a second air gap with said armature, first electromagnetic means for producing a magnetic flux in a first direction across said first air gap and in a first direction across said second air gap, and second electromagnetic means for producing a magnetic flux across said second air gap in a direction opposite to said first direction therein and for producing a magnetic flux across said first air gap in said first direction therein, whereby energization of either said first or second electromagnetic means alone results in a magnetic fiux across said first air gap and across said second air gap, while simultaneous energization of said first and second electromagnetic means results in addition of aiding flux in said first air gap and cancellation of opposing flux in said second air gap.

2. A shuntfield relay comprising an armature, first magnetic rneans forming a first air gap with said armature, second magnetic means forming a second air gap with said armature, first electromagnetic means for producing a magnetic flux in a first direction across said first air gap and in a first direction across said second air gap, and second electromagnetic means for producing a magnetic flux across said second air gap in a direction opposite to said first direction therein and for producing a magnetic fiux across said first air gap in said first direction, whereby energization of either said first or second electromagnetic means alone results in a magnetic flux across said second air gap, while simultaneous energization of said first and second electromagnetic means results in addition of aiding flux in said first air gap and cancellation of opposing flux in said second air gap.

3. A shuntfield relay in accordance with claim 2, wherein said second air gap is small relative to said first air gap when said armature is in an inactuated position, whereby said armature is retained in such inactuated position upon energization of said first or second electromagnetic means alone.

4. A shuntfield relay in accordance with claim 2, wherein movement of said armature from said inactuated position to an actuated position in response to the simultaneous energization of said first and second electromagnetic means results in an increase in the length of said second air gap and a decrease in the length of said first air gap,

5. A shuntfield relay in accordance with claim 4, wherein said second magnetic means also forms a third air gap with said armature, said movement of said armature also resulting in a decrease in the length of said third air gap.

6. A shuntfield relay in accordance with claim 2, wherein the flux produced in said second air gap by said first electromagnetic means is substantially equal to the flux produced in said second air gap by said second electromagnetic means, whereby a substantially zero resultant flux is produced in said second air gap upon simultaneous energization of said first and second electromagnetic means.

7. A shuntfield relay in accordance with claim 2, where in said first electromagnetic means includes a core portion of a material exhibiting high magnetic remanence.

8. A selector network for indicating the signals in a coordinate signal field formed by a row and column matrix of selector elements, comprising: selector elements each including an armature, first magnetic means forming a first air gap with said armature, second magnetic circuit means forming a second air gap with said armature, first electromagnetic means for producing a magnetic flux in a first direction across said first air gap and in a first direction across said second air gap and second electromagnetic means for producing a magnetic flux across said second air gap in a direction opposite to said first direction therein and for producing a magnetic flux across said first air gap in said first direction therein, said first electromagnetic means of the selector elements in respective rows of the matrix being responsive only to signals in the respective row in which the selector element is located, said second electromagnetic means of the selector elements in respective columns of the maxtrix being responsive only to signals in the respective column in which the selector element is located, whereby a signal in any given row or column alone results in a magnetic flux across the first air gap and across the second air gap of the associated selector elements, while the simultaneous application of signals in a given column and a given row results in addition of aiding flux in said first air gap and cancellation of opposing flux in said second air gap of the respective selector element associated with said row signal and said column signal.

9. A selector network for indicating the signals in a coordinate signal field formed by a row and column matrix of selector elements, comprising: selector elements each including an armature, first magnetic means forming a first air gap with said armature, second magnetic means forming a second air gap with said armature, first electromagnetic means for producing a magnetic flux in a first direction across said second air gap and second electromagnetic means for producing a magnetic flux across said second air gap in a direction opposite to said first direction therein and for producing a magnetic fiux across said first air gap in said first direction therein, said first electromagnetic means of the selector elements in respective rows of the matrix being responsive only to signals in the respective row in which the selector element is located, said second electromagnetic means of the selector elements in respective columns of the matrix being responsive only to signals in the respective column in which the selector element is located, whereby a signal in any given row or column alone results in a magnetic flux across the second air gap of the associated selector elements, while the simultaneous application of signals in a given column and a given row results in addition of aiding flux in said first air gap and cancellation of opposing flux in said second air gap of the respective selector element associated with said row signal and said column signal.

10. A selector network according to claim 9 further comprising barring means operatively associated with the armature means in each respective row of selector elements, said barring means of a given row being activated by the actuation of any one of the armatures of that same row to prevent the nonactuated armatures in such row from being actuated until said actuated armature has been returned to a non-actuated position.

11. A selector network for indicating the signals in a coordinate signal field formed by a row and column matrix of selector elements, comprising: selector elements each including an armature, first magnetic means forming a first air gap with said armature, second magnetic means forming a second air gap with said armature, first electromagnetic means for producing a magnetic flux in a first direction across said first air gap and in a first direction across said second air gap, and second electromagnetic means for producing a magnetic flux across said second air gap in a direction opposite to said first direction therein and for producing a magnetic flux across said first air gap in said first direction therein, the first electromagnetic means of the selector elements in respective rows of the matrix being responsive only to signals in the respective row in which the selector element is located, the second electromagnetic means of the selector elements in respective columns of the matrix being responsive only to signals in the respective column in which the selector element is located, whereby a signal of any given row or column alone results in a magnetic flux across the second air gap of the associated selector element, while the simultaneous application of signals in a given column and a given row results in addition of aiding flux in said first air gap and cancellation of opposing flux in said second air gap of the respective selector element associated with said row signal and said column signal, said first electromagnetic means comprising an elongated coil for each row, said coil being common to all of the selector elements contained in such row.

12. A selector network for indicating the signals in a coordinate signal field formed by a row and column matfix of selector elements, comprising: selector elements each including an armature, first magnetic means forming a first air gap with said armature, second magnetic means forming a second air gap with said armature, first electromagnetic means for producing a magnetic flux in a first direction across said first air gap and in a first direction across said second air gap and second electromagnetic means for producing a magnetic flux across said second air gap in a direction opposite to said first direction therein and for producing a magnetic flux across said first air gap in said first direction therein, said first electromagnetic means of the selector elements in respective rows of the matrix being responsive only to signals in the respective row in which the selector element is located, said second electromagnetic means of the selector elements in the respective columns of the matrix being responsive only to signals in the respective column in which the selector element is located, whereby a signal in any given row or column alone results in a magnetic flux across the second 23 24 air gap of the associated selector elements, while the References Cited simultaneous application of signals in a given column and UNITED STATES PATENTS a given row results in addition of aiding flux in said first air gap and cancellation of opposing flux in said second g g igfi 'g' 'g air gap of the respective selector element associated with 5 said row signal and said column signal, said second elec- GEORGE HARRIS Primary Examiner.

tromagnetic means comprising an elongated coil for each column, said elongated coil being common to all selector US. Cl. X.R.

elements contained in such column. 335268, 229

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 3,417,353 December 17, 1968 Sten Daniel Vigren et al.

It is certified that error appears in the above identified patent and that said Letters Patent are hereby corrected as shown below:

Column 1, line 51, "Each" should read At each Columl 6, lines 50 and 5S, "magnet", each occurrence, should read magnetic Column 10, line 20, after "core" insert part Column ll, line 16, "curent" should read current Column 13, line 54, "it" should read It Column 14, line 2, afte1 "than" insert H the line 25, after "first" insert air Column 16, lines 50 and 51, "magneto-motive" should read magneto-motoric Column 18, line 32, "K26" should read K62 line 47, "link", second occurrence, should read links Column 19, line 29, after "hand" insert a comma; line 30, after the closing parenthesis cancel the comma; line 71, after "609" insert a comma.

Signed and sealed this 17th day of March 1970.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. WILLIAM E. SCHUYLER, JR. Attesting Officer Commissioner of Patents 

